NPT Fitting

What applications use NPT hydraulic fittings?

NPT fittings are primarily used in North American standard fluid and gas transmission systems, and are widely used in oil and gas, chemical, engineering and construction machinery, water treatment, and industrial pipelines—scenarios requiring high-pressure sealed connections.

Industrial Applications: High-pressure, high-temperature applications such as petroleum, chemical, and water treatment.

Pipeline Systems: Used for connecting water supply, drainage, gas, and steam pipelines.

Hydraulic Systems: Compression fittings and flared fittings are commonly used for hydraulic piping connections and are widely used in the construction, agriculture, oil and gas industries, and other sectors.

Pneumatic Systems: Used for connecting pneumatic piping for compressed air and other applications in industrial and medical applications.

What are the advantages of using NPT hydraulic couplings?

NPT hydraulic couplings offer unique advantages that make them suitable for medium- and high-pressure systems and ensure reliable connections.

Compact structure and strong sealing: Utilizing a 1:16 taper and a 60° thread angle, they lock directly via the threaded conical surface. Combined with PTFE tape or anaerobic adhesive, they achieve a highly reliable seal and excellent resistance to pulsating pressure.

Corrosion and high-temperature resistance: These connectors are typically made of materials such as stainless steel, carbon steel, and brass, capable of withstanding corrosive media such as acids, alkalis, and salts, as well as high temperatures. Appropriate materials can be selected based on the operating environment, meeting most industrial hydraulic requirements.

High versatility based on US standards: Compliant with US national standards, with strict dimensional and tolerance requirements, ensuring safe and reliable connections and high interchangeability.

Easy installation and low cost: Quick assembly is achieved using only a standard wrench and sealing medium (PTFE tape or sealant), requiring no welding or special tools, resulting in high construction efficiency.

How to determine the system requires an NPT hydraulic fitting?

Whether your system requires an NPT fitting depends primarily on the equipment’s origin, thread design, and whether a self-sealing thread is required.

Determine the equipment’s origin and standard: NPT threads are a US standard, widely used in hydraulic, pneumatic, and piping equipment manufactured in North America.

Check the corresponding thread: NPT threads are tapered, gradually tapering from beginning to end, with a 60-degree thread angle. The matching connector should also be tapered with the same thread angle.

Determine the sealing method: NPT typically lacks O-rings or flat gaskets for sealing. NPT threads achieve sealing through thread mating and sealing materials. If the interface has obvious sealing grooves or requires flattening the sealing ring to prevent leakage, it is not NPT.

Check historical maintenance records or consult a professional connector manufacturer: Every maintenance and parts replacement should be recorded. If no record exists, take photos and send them to the hydraulic connector supplier for professional assistance.

Frequently Asked Questions About NPT Fittings

Can you use a straight thread with NPT?

No, NPT threads have a tapered surface and cannot form a seal with straight threads.

Do you need Teflon tape on NPT?

Teflon tape (also known as PTFE tape or thread sealing tape) is commonly used for sealing NPT threads. Teflon tape offers excellent sealing properties and chemical resistance, effectively filling tiny gaps between threads and preventing liquid or gas leakage.

How to measure NPT fittings?

Use calipers to measure the outside diameter (for male threads) or inside diameter (for female threads) of the pipe. Because NPT threads are tapered, their diameter gradually increases from the opening to the pipe body. Therefore, the most accurate measurement point is usually the second or third thread. Please refer to the table above comparing common NPT sizes to their actual outside diameters.
Thread pitch (TPI) refers to the number of threads per inch. You will need a thread gauge to measure this.
By combining the outside diameter and pitch measurements, you can accurately determine the size of the NPT thread.
For detailed measurement methods, please refer to this article: How to Measure NPT Fittings?

How to seal an NPT fitting?

To seal NPT fittings, thread sealant is necessary because threads alone don’t create a perfect seal. The tapered design of NPT (National Pipe Taper) fittings creates a mechanical lock and a metal-to-metal seal, but it’s not foolproof. Sealant or PTFE tape fills the tiny gaps between the threads, preventing leaks.

Where can I buy NPT Hydraulic Fittings?

You can search for NPT fittings suppliers or manufacturers on Google and visit their official websites.

Search for product models on B2B websites such as Alibaba and Amazon, and contact the suppliers to inquire about specific fitting data.

Attend offline exhibitions, such as PTC and CTT, to find trustworthy suppliers.

Finally, you can conduct on-site inspections, visiting the hydraulic fitting manufacturing plant to observe the production process and compare quality.

You are welcome to visit our factory at any time. We have a comprehensive product line, offering a variety of options for both custom and mass production.

With years of industry experience, we can not only recommend the most suitable hydraulic fittings but also strictly control every step from raw materials and production processes to finished product inspection, ensuring you receive satisfactory products.

Prices are competitive; we are a factory direct supplier. Contact us for a quote.